The invention pertains to the fabrication of field effect transistors (FETs), particularly heterostructure FETs (HFETs). More particularly, the invention is applicable to a device which is a heterostructure insulated gate (HIG) FET requiring a minimal leakage current between the gate pad and the remaining FET structure and a method for producing the device.
Physical contact between the gate pad and the heterostructure wafer of a HFET creates an undesirable high current leakage between the gate pad and the wafer. Since current leakage increases drastically with increased temperature, and results in high power consumption, minimized current leakage is essential for HFET operation at high temperatures.